An electronic power supply takes as input a voltage source that can vary in magnitude and is therefore called unregulated. The output of an electronic power supply is usually a voltage source that is fixed in magnitude and is therefore called regulated. A DC to DC converter is an electronic power supply which takes as an input an unregulated DC voltage and provides as output a regulated DC voltage. Current is drawn from the output of an electronic power supply by the attached load. If the attached load is located far from the output terminals of a power supply then a voltage drop will occur in the distribution path resulting in a lower voltage at the load than at the power supply's output terminals. This voltage drop is a result of the load current flowing through the distribution impedance. The result of the distribution voltage drop is poor regulation at the load point. This can cause problems in some systems.
Normally an electronic power supply senses the voltage at its output terminals and regulates the voltage at this point. For systems where distribution voltage drops are a problem, a single pair of sense pins may be provided. The sense pins monitor the voltage at the load point and then the power supply adjusts its output so that the voltage directly across the load is regulated. This single point sensing is commonly used by many power supply manufacturers.
Single point sensing works very well when a single load element is placed across a power supply's output. If a power supply is to provide a single output for multiple loads than each of these loads has to be connected across a single point if single point load sensing is to work correctly. In some applications the single point connection of many loads is easy to achieve. However, in many places a compromise solution has to be implemented. One compromise is to connect the single pair of sense pins at the "electrical center" of a distribution system and thus regulate that point.